/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later. See the lgpl.txt file in the root directory
 * or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.proxy.pojo;

import java.io.Serializable;
import java.lang.reflect.Method;

import org.hibernate.engine.spi.EntityKey;
import org.hibernate.engine.spi.SharedSessionContractImplementor;
import org.hibernate.internal.util.MarkerObject;
import org.hibernate.proxy.AbstractLazyInitializer;
import org.hibernate.type.CompositeType;

/**
 * Lazy initializer for POJOs
 *
 * @author Gavin King
 */
public abstract class BasicLazyInitializer extends AbstractLazyInitializer
{

	protected static final Object INVOKE_IMPLEMENTATION = new MarkerObject("INVOKE_IMPLEMENTATION");

	protected final Class<?> persistentClass;
	protected final Method getIdentifierMethod;
	protected final Method setIdentifierMethod;
	protected final boolean overridesEquals;
	protected final CompositeType componentIdType;

	private Object replacement;

	protected BasicLazyInitializer(String entityName, Class<?> persistentClass, Serializable id,
			Method getIdentifierMethod, Method setIdentifierMethod, CompositeType componentIdType,
			SharedSessionContractImplementor session, boolean overridesEquals)
	{
		super(entityName, id, session);
		this.persistentClass = persistentClass;
		this.getIdentifierMethod = getIdentifierMethod;
		this.setIdentifierMethod = setIdentifierMethod;
		this.componentIdType = componentIdType;
		this.overridesEquals = overridesEquals;
	}

	protected abstract Object serializableProxy();

	protected final Object invoke(Method method, Object[] args, Object proxy) throws Throwable
	{
		String methodName = method.getName();
		int params = args.length;

		if (params == 0)
		{
			if ("writeReplace".equals(methodName))
			{
				return getReplacement();
			}
			else if (!overridesEquals && "hashCode".equals(methodName))
			{
				return System.identityHashCode(proxy);
			}
			else if (isUninitialized() && method.equals(getIdentifierMethod))
			{
				return getIdentifier();
			}
			// ------------------------------更改开始------------------------------
			// getID方法直接获取，不走代理
			else if (method.getName().equals("getId"))
			{
				return getIdentifier();
			}
			// ------------------------------更改结束------------------------------
			else if ("getHibernateLazyInitializer".equals(methodName))
			{
				return this;
			}
		}
		else if (params == 1)
		{
			if (!overridesEquals && "equals".equals(methodName))
			{
				return args[0] == proxy;
			}
			else if (method.equals(setIdentifierMethod))
			{
				initialize();
				setIdentifier((Serializable) args[0]);
				return INVOKE_IMPLEMENTATION;
			}
		}

		// if it is a property of an embedded component, invoke on the "identifier"
		if (componentIdType != null && componentIdType.isMethodOf(method))
		{
			return method.invoke(getIdentifier(), args);
		}

		// otherwise:
		return INVOKE_IMPLEMENTATION;

	}

	private Object getReplacement()
	{
		final SharedSessionContractImplementor session = getSession();
		if (isUninitialized() && session != null && session.isOpen())
		{
			final EntityKey key = session.generateEntityKey(getIdentifier(),
					session.getFactory().getMetamodel().entityPersister(getEntityName()));
			final Object entity = session.getPersistenceContext().getEntity(key);
			if (entity != null)
			{
				setImplementation(entity);
			}
		}

		if (isUninitialized())
		{
			if (replacement == null)
			{
				replacement = serializableProxy();
			}
			return replacement;
		}
		else
		{
			return getTarget();
		}

	}

	public final Class<?> getPersistentClass()
	{
		return persistentClass;
	}

}
